Category: Standards and Guidelines

WCAG 2.0

Also known as: WCAG 2.0, Web Content Accessibility Guidelines 2.0

Simply put

WCAG 2.0 is a set of internationally recognized guidelines, published by the World Wide Web Consortium (W3C) through its Web Accessibility Initiative (WAI), for making web content more accessible to people with disabilities. Released in December 2008, it provides a wide range of recommendations that websites, applications, and other web content can follow. It is the foundation for later versions, including WCAG 2.1 and WCAG 2.2, which build on the same structure.

Formal definition

WCAG 2.0 is a W3C Recommendation published on December 11, 2008 that defines requirements for making web content more accessible to people with disabilities. It establishes the conformance model reused by later versions: content that conforms to WCAG 2.1 or WCAG 2.2 is intended to also conform to WCAG 2.0. The guidelines are organized under testable success criteria assigned to conformance levels A, AA, and AAA, with Level AA commonly cited as a target in accessibility practice. WCAG 2.0 addresses web sites, web applications, and related web content, and serves as the baseline that WCAG 2.1 and WCAG 2.2 extend rather than replace. WCAG 2.0 is a technical standard published by the W3C/WAI; it is not itself a law, and any legal weight it carries in a given jurisdiction depends on applicable regulation, agency guidance, or case law, which should be evaluated with qualified legal counsel.

Why it matters

WCAG 2.0, published as a W3C Recommendation on December 11, 2008, established the technical foundation for how web accessibility is defined and measured internationally. Rather than being replaced by later releases, it serves as the baseline that WCAG 2.1 and WCAG 2.2 extend: content conforming to those later versions is intended to also conform to WCAG 2.0. This continuity means that the conformance model, structure, and many of the success criteria organizations rely on today trace directly back to WCAG 2.0.

Because it introduced testable success criteria organized under conformance levels A, AA, and AAA, WCAG 2.0 gave accessibility practitioners, designers, and legal teams a shared vocabulary and a measurable benchmark. Level AA is commonly cited as a target in accessibility practice. This shared reference point matters for procurement, design review, and remediation planning, since teams across different organizations and jurisdictions can point to the same criteria when describing what accessible web content should do.

It is important to note that WCAG 2.0 is a technical standard published by the W3C and its Web Accessibility Initiative; it is not itself a law. Any legal weight it carries in a given jurisdiction depends on applicable regulation, agency guidance, or case law, and organizations should evaluate their obligations with qualified legal counsel. Meeting WCAG 2.0 success criteria also does not by itself guarantee an accessible experience for every user, as conformance and real-world usability are related but distinct.

Who it's relevant to

Accessibility engineers and QA testers

WCAG 2.0 provides the baseline set of testable success criteria against which web content is evaluated. Because later versions reuse its conformance model, understanding WCAG 2.0 helps testers interpret results consistently. Effective evaluation generally combines automated tooling with manual and assistive technology testing, since automated checks capture only part of the picture.

UX designers and developers

Designers and developers use WCAG 2.0 success criteria and conformance levels, commonly targeting Level AA, as a shared reference for building accessible interfaces. Because WCAG 2.1 and WCAG 2.2 extend rather than replace WCAG 2.0, familiarity with the 2.0 baseline supports work that also aligns with the newer versions.

Compliance officers and business leaders

WCAG 2.0 offers a measurable benchmark useful for procurement, vendor evaluation, and internal accessibility goals. Leaders should recognize that WCAG 2.0 is a technical standard, not a law, and that its role in any legal obligation depends on jurisdiction-specific regulation, agency guidance, and case law.

Legal counsel

Counsel evaluating accessibility obligations may encounter WCAG 2.0 as a referenced benchmark. Its legal significance varies by jurisdiction and evolves through regulation and case law, so its application to a specific situation should be assessed by qualified legal professionals rather than assumed from the standard alone. This entry is informational and is not legal advice.

Inside WCAG 2.0

Four Principles (POUR)

WCAG 2.0 is organized around four foundational principles stating that content must be Perceivable, Operable, Understandable, and Robust. These principles frame all of the guidelines and success criteria beneath them.

Guidelines

Under the four principles sit a set of guidelines that provide the general goals authors should work toward to make content more accessible. The guidelines themselves are not directly testable but organize the success criteria.

Success Criteria

Each guideline includes testable success criteria written to be verifiable through manual review, automated tools, or a combination. These criteria are the requirements against which conformance is measured.

Conformance Levels A, AA, and AAA

Success criteria are assigned to three conformance levels. Level A represents the most basic requirements, Level AA addresses common and significant barriers, and Level AAA represents the highest level. Level AA is the level most commonly cited as a target in policies and settlements.

Technology-Neutral Design

WCAG 2.0 was written to be broadly applicable across web technologies rather than tied to specific techniques, so that it can remain relevant as technologies change. Supporting techniques and failures are published separately as informative guidance.

Publication by the W3C/WAI

WCAG 2.0 is a technical standard published by the World Wide Web Consortium (W3C) through its Web Accessibility Initiative (WAI). It is a set of guidelines, not a law in itself.

Common questions

Answers to the questions practitioners most commonly ask about WCAG 2.0.

Does the ADA legally require compliance with WCAG 2.0?

Not directly. The Americans with Disabilities Act is a US civil rights law and does not itself codify detailed web technical specifications such as WCAG 2.0. However, courts, settlements, and some agency guidance have often referenced WCAG (frequently at Level AA) as a benchmark for what constitutes accessible web content. Whether WCAG 2.0 applies in a given situation depends on the specific regulation, settlement, or guidance involved, so the reference should always be attributed to that source. This is general information and not legal advice; consult qualified legal counsel regarding your specific obligations.

If our site conforms to WCAG 2.0, does that guarantee it is accessible and legally compliant?

No. Meeting WCAG 2.0 success criteria does not by itself guarantee an accessible experience for all users, nor does it guarantee immunity from legal claims. Conformance, usability, and legal compliance are distinct. Automated testing detects only a portion of potential issues, so manual review and testing with assistive technologies are generally needed to evaluate real-world accessibility. Legal requirements also continue to evolve through regulation and case law, and this entry is not a substitute for advice from qualified legal counsel.

What conformance level of WCAG 2.0 is most commonly targeted?

Level AA is the conformance level most commonly cited as a target. WCAG 2.0 defines three levels: A, AA, and AAA. Meeting AA generally requires satisfying all Level A and Level AA success criteria. Level AAA represents the most stringent set of criteria and is not typically expected to be met in full across an entire site.

How does WCAG 2.0 relate to later versions like WCAG 2.1 and 2.2?

WCAG 2.0 is the earliest of the WCAG 2.x guidelines published by the W3C through the Web Accessibility Initiative. WCAG 2.1 and 2.2 build on WCAG 2.0 and add success criteria, including criteria addressing areas such as mobile and additional needs, while remaining backward compatible. When identifying which requirements apply, it is important to distinguish which criterion belongs to which version and level, since later versions introduced criteria not present in WCAG 2.0.

Can automated testing tools verify WCAG 2.0 conformance on their own?

No. Automated testing tools detect only a portion of WCAG 2.0 issues. Many success criteria require human judgment, so manual review and testing with assistive technologies are generally required to assess conformance meaningfully. Automated results are best treated as one input into a broader evaluation process rather than as a complete measure of conformance.

What are the guiding principles that organize WCAG 2.0 success criteria?

WCAG 2.0 is organized around four principles, commonly summarized as perceivable, operable, understandable, and robust. Under these principles sit guidelines, and under the guidelines are the testable success criteria assigned to levels A, AA, and AAA. This structure is intended to help teams organize their evaluation and implementation work around how users perceive, operate, and understand content, and how reliably that content works with assistive technologies.

Common misconceptions

The ADA legally requires conformance with WCAG 2.0.

The ADA is a US civil rights law and does not itself contain detailed web technical specifications. WCAG 2.0 has often been referenced as a benchmark in settlements, regulations, and agency guidance rather than being codified as a universal legal mandate. Whether and how it applies depends on the specific authority, regulation, or case, and readers should consult qualified legal counsel.

Meeting WCAG 2.0 success criteria guarantees an accessible experience and immunity from legal claims.

Conformance with success criteria is distinct from real-world usability and from legal compliance. Meeting the criteria does not guarantee that all users can use the content effectively, nor does it guarantee protection from claims. Manual and assistive technology testing remain necessary.

Passing automated accessibility checks means a site conforms to WCAG 2.0.

Automated testing detects only a portion of potential issues. Many WCAG 2.0 success criteria require human judgment, so manual review and testing with assistive technologies are required to assess conformance meaningfully.

Best practices

Target WCAG 2.0 Level AA as a baseline, since it is the level most commonly cited in policies and settlements, while recognizing that later versions such as WCAG 2.1 and 2.2 add further criteria.

Combine automated tools with manual review and testing using assistive technologies, because automated checks detect only a portion of issues.

Evaluate conformance against the specific, testable success criteria rather than the higher-level principles or guidelines alone.

Treat conformance as separate from usability, and validate real-world experience with users, including people who rely on assistive technologies.

Confirm which legal or regulatory authority applies to your context and consult qualified legal counsel, as WCAG 2.0 is a technical standard and not a law in itself.

Document your testing methods, results, and remediation efforts, and revisit them as standards, regulations, and case law evolve.